Altadena, CA tap water
Supplied mostly by Foothill Municipal Water Dist., plus 3 other utilities. Here's what the water means for your fish.
Disinfectant
Chloramine
Your water is treated with chloramine. Unlike chlorine, it doesn't gas off when water sits out, and many pitcher and fridge filters aren't rated to remove it. Conditioners that list chloramine on the label break it apart, which frees about 0.34 ppm of ammonia here. Some utilities switch to plain chlorine for a few weeks a year.
Safety for fish and shrimp
Ammonia (with conditioner)
Estimate0.34–0.73 ppm (Low)
Typical 0.34 ppm
This is what a conditioner frees when it breaks the chloramine apart. A cycled filter clears it within a day.
Estimated from the chloramine level Pasadena Water and Power (PWP) reports (2024).
Nitrite (NO₂)
Not detected (Low)
Not detected in testing, so any nitrite in your tank comes from the tank itself.
From California Water Board lab results (2023).
Nitrate (NO₃)
Supplier's figureUp to 28 ppm (Low)
Typically not detected
Not detected in testing, so water changes lower your tank's nitrate well.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal., which supplies Foothill Municipal Water Dist.; Pasadena Water and Power (PWP)'s 2024 water quality report; California Water Board lab results (2023–2026).
Copper at home taps
0.09–0.26 ppm (Worth knowing)
Typical 0.14 ppm
Shrimp and snails are sensitive to copper. Water that sits in household pipes picks up the most; it drops once the tap has run for a minute.
From Pasadena Water and Power (PWP)'s 2024 water quality report; California Water Board lab results (2024–2026).
Chlorine or chloramine at the tap
1.4–3 ppm
Typical 1.4 ppm
At tap levels, chlorine and chloramine are toxic to fish, shrimp and the bacteria in a filter. Water conditioners are made for this range.
Published by your utility: Pasadena Water and Power (PWP)'s 2024 water quality report.
Water chemistry
General hardness
Supplier's figure82–430 ppm
Typical 234 ppm
Hard. Ideal for livebearers and African cichlids. Soft-water species may struggle to breed.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal., which supplies Foothill Municipal Water Dist.; Pasadena Water and Power (PWP)'s 2024 water quality report; California Water Board lab results, measured before treatment (2023–2026).
Carbonate hardness (alkalinity)
Supplier's figure68–210 ppm
Typical 106 ppm
Moderate buffering. pH should stay fairly steady.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal., which supplies Foothill Municipal Water Dist.; Pasadena Water and Power (PWP)'s 2024 water quality report; California Water Board lab results, measured before treatment; California Water Board lab results (2023–2026).
pH
Supplier's figure7.1–8.7
Typical 8.2
Alkaline. Many utilities raise pH to protect pipes. Stability matters more than the exact number.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal., which supplies Foothill Municipal Water Dist.; Pasadena Water and Power (PWP)'s 2024 water quality report; California Water Board lab results, measured before treatment (2023–2026).
Total dissolved solids
Supplier's figure145–690 ppm
Typical 535 ppm
A rough measure of everything dissolved in the water. RO water reads near 0, so TDS is a quick way to compare waters.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal., which supplies Foothill Municipal Water Dist.; Pasadena Water and Power (PWP)'s 2024 water quality report; California Water Board lab results, measured before treatment (2023–2026).
Who supplies Altadena, CA
Foothill Municipal Water Dist.
Serves 50% of residents · Buys water from Metropolitan Water Dist. of So. Cal. · Chloramine
- 2024 water quality report
Pasadena Water and Power (PWP)
Serves 19% of residents · Buys water from Metropolitan Water Dist. of So. Cal. · Chloramine
Lincoln Avenue Water Co.
Serves 17% of residents · Lake or river water · Chloramine
Rubio Canon Land & Water Association
Serves 11% of residents · Lake or river water · Chloramine
Our data comes from public records and is still incomplete. Many utilities don't publish every number, so we're adding more all the time. Your city's range is a starting point: testing your own tap is the only way to know exactly what's in it.
Tap water lookup covers US cities only for now. Want to know why it matters? Read our story on tap water.
Compiled by Shoal & Stem from public records. Free to cite with a link.